In recent years, field-sequential drive has been drawing attention as a method for driving a liquid crystal display device that displays a color image. In typical field-sequential drive, one frame for displaying one screen is divided into three fields, and red, green, and blue LEDs (light-emitting diodes), which constitute a backlight source, are sequentially switched around and lit up for their respective fields. In synchronization with the lighting of the LEDs, data voltages, which are generated on the basis of image data corresponding to the colors of the light, are sequentially applied to a liquid crystal display panel, thereby controlling the transmission state thereof, such that additive color mixing takes place on the retina of the viewer. As a result, the field-sequential drive, unlike drive using color filters, renders it possible to display a color image without a plurality of subpixels formed in each pixel, thereby achieving higher resolution. Moreover, it is not necessary to provide color filters, which have a high level of backlight absorption, resulting in enhanced light use efficiency of the LEDs.
To enable such a liquid crystal display device to be used also as a see-through display device allowing a background to be seen, there is a method in which some values for color depth levels are allocated to transparency range. For example, in the case where data for an image in each color included in image data is 8-bit image data, a color image is displayed by representing red (R), green (G), and blue (B) images with 255 levels from 0 to 254, rather than 256 levels from 0 to 255, and the pixel value (255, 255, 255) is used for see-through display. Thus, the liquid crystal display device renders it possible to achieve not only color image display but also transparency to allow a background to be seen therethrough.
Furthermore, in the case of a liquid crystal display device which displays an image based on image data which includes display image data for image display and lighting-pattern image data for controlling the pattern of lighting up a backlight, the size of the display image data is small, which results in image deterioration. Therefore, in the case of a liquid crystal display device described in Patent Document 1, the display image data and the lighting-pattern image data are provided in a time division manner in order to keep the size of the display image data from becoming small and thereby preventing image deterioration.